How Come You Feel Cold When You Have a Fever?

By Howard J. Bennett

Having a fever can make you feel miserable and creates some odd sensations. Instead of feeling hot, people with fever usually feel cold. They also may experience chills, rapid breathing and muscle aches. You can even wake up in a pool of sweat as the fever breaks.

Body temperature results from a balance between the heat generated by our cells and the heat “lost” to the environment. Heat created by our cells comes from the energy used to keep us alive. Heat is lost through our skin and the air we breathe out. Human beings have an average temperature of 98.6 degrees Fahrenheit. The brain monitors body temperature and controls our bodies to keep our temperature within the normal range.

If the brain detects a drop in temperature, it directs the body to make a number of changes to correct the imbalance. Those changes include increasing heat production within the body (by shivering, for example) and reducing heat loss to the environment. Heat loss is reduced by decreasing blood flow to the skin.

If the brain senses a rise in temperature, the opposite changes occur. This is accomplished by increasing blood flow to the skin, breathing faster and by sweating. (When your sweat evaporates, it cools the body.)

If you get a fever when you’re sick, it’s because your brain has told your body to get hotter. There is evidence that many germs don’t thrive as well if you have a fever, so fever could be a way the body protects itself when you’re ill. Medicine can make fevers drop (until the medicine wears off), but it’s not always effective. With some infections (like the flu) you can still be hot even though you take fever-reducing medicine.

Lots of parents worry that fever is harmful, but the fever that accompanies illness is not dangerous. Doctors are also concerned when kids develop fevers, but we are concerned about the cause of the fever rather than the temperature itself. We treat fever to make children more comfortable (which in turn makes them more willing to drink and stay hydrated) not because it’s essential to reduce the fever.

So the next time you’re sick, do yourself and your parents a favor by resting, drinking lots of fluids and eating when you can. Oh, and don’t forget: A teaspoon of sugar (and a little TV) helps the medicine go down!


© 2012 Howard J. Bennett. All Rights Reserved.
(First published in the Washington Post 12/7/09.)

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